with packed filtering material

Full Title

Methods or installations for obtaining or collecting drinking water or tap water (treatment of water C02F) > from underground > Obtaining and confining water by means of wells (applicable to a combination of water and other liquids or to other liquids only E21B43/00) > Component parts of wells > Well filters (filters in general B01D24/00 - B01D35/00) > formed of loose materials, e.g. gravel > with packed filtering material